Method of making plow bottom parts, particularly moldboards



June 30, 1953 w. E. RUSKA 2,643,438

METHOD OF MAKING PLOW BOTTOM PARTS, PARTICULARLY MOLDBOARDS Filed Jan.12, 1951 FIGi INVENTOR- WiniamE. Ruska/ A TTORNEY Patented June 30, 1953UNITED STATES TENT OFFICE METHOD OF MAKING PLOW BQTTOM PARTS,PARTICULARLY MOLDBOARDS Application January 12, 1951, Serial No. 205,768

3 Claims.

This invention relates to a method of making plow bottom parts,particularly moldboards, and has for an object the provision ofimprovements in this art.

One of the particular objects of the invention is to provide a method ofmaking plow bottom parts, particularly moldboards, with a hard jacketand a soft tough core which requires the minimum of surface finishingoperations after hardening, whereby to leave a hard jacket or shell ofuniform depth over the entire surface area of the part.

Another object is to provide a method of making plow parts wherein, ofthe total of operations required, the maximum number of operations areperformed on flat stock and the minimum number of operations on thefinal curved stock.

Another object is to provide a method of making plow bottom parts whichpromotes improved and more uniform annealing of the stock.

Another object is to provide a method in which the heat-treating heat isused for subsequent forming and hardening operations.

Another object is to provide a method of making plow bottom parts whichgives greater econonly and facility of handling in the process as awhole.

The above and other objects and advantages of the invention will beapparent from the following description of an iilustrative embodimentthereof, reference being made to the accompanying drawings, wherein:

Fig. l is a perspective view of a rolled strip from which the parts areto be cut;

Fig. 2 shows a stack of flat strips during annealing after hot rolling;

Fig. 3 is a plan view showing how blanks are cut from the strip, holesbeing punched in the same operation;

Fig. 4 shows the surface finishing operation on the fiat stock;

Fig. 5 shows the chemical heat-treating operation, as in a carburizingfurnace;

Fig. 6 illustrates a die shaping operation;

Fig. 7 illustrates a quenching operation; and

Fig. 8 shows the final plow bottom assembly.

The specific plow bottom part which is taken for illustration inconnection with the present method is a moldboard is having bolt holes Hwith squared countersunk portions for bolts for securing the part to aplow bottom saddle or frog. The moldboard has a lower joint edge I?adapted to fit a share It (Fig. 8).

It is desired that the finished moldboard will have a hardwear-resisting jacket or shell and a soft tough core. If a hard jacketedstrip is taken at the start all of the forming operations are madediflicult and expensive; whereas if a soft blank is used, such as softhigh-tensile steel, it may have many of the shaping operations performedbefore the hard jacket is formed. Besides, the soft material is muchless expensive than the hard clad (soft center steel) material.

The original stock from which the parts are made consists of a flathot-rolled strip I5 (Fig. 1) which readily stacks and holds its heat forannealing, as shown in Fig. 2.

After annealing, the strip is cut to form blanks (Fig. 3) and in thesame operation the bolt holes H may be formed. In a succeeding operationthe square countersunk portions of the holes are formed.

Next, and while the stock is still fiat and soft, the surfaces areground or polished, or both, to provide the final thickness dimensions,as shown in Fig. 4. Plow shapes are quite complex and it is a slow andexpensive job to grind them in their final shape, and this is especiallytrue when the surface has been hardened. In the flat soft state the maingrinding can be done for a small part of what the cost of finishgrinding would be. While a slight final grinding or polishing may benecessary it is not nearly so expensive as it would be if all grindinghad to be performed in the final state. By grinding in the flat it ispossible to use wide-faced cylindrical grinding rolls or even to grindby automatic machines. Final grinding of contoured shapes must be doneby hand, as by cradles with small grinding rolls and requires highlyskilled labor, hence is very expensive.

The ground blanks are placed edgewise and spaced apart in a tray I9(Fig. 5) and heated in a suitable chemical atmosphere to give them ahard or hardenable outer jacket completely surrounding a soft toughcore. In the present case the blanks are given a carburizing treatment,as in a carburizing furnace 20, a number of blanks being carried by eachtray.

Subsequent to the carburizing treatment the blanks are taken out one byone and, with the same heat, are forged in a die press 22 to take theirfinal shape.

While still hot from the press the blanks, when at the propertemperature, are quenched in a bath 24, as of a suitable salt solution(Fig. 7) to form a hard jacket. The hardened parts may be reheated andannealed if necessary.

Finally the shaped and hardened moldboard is secured, along with otherparts, on a plow saddle (Fig. 8). If necessary the assembled parts maybe given a final grinding operation to make the joint and bolt headzones smooth and even. The smooth surface may then be oiled and polishedto a micro-finish, if desired.

It may now be seen that the method is very efiicient and economical. Bygrinding the parts while fiat and unhardened and by shaping the partswhile hot and unhardened, great overall economy of operation isattained. Moreover, the hard jacket does not have to be ground to anyextent in the final form, thus avoiding the expense of such finalgrinding operations and leaving a jacket of uniform thickness on thepart.

While one embodiment of the invention has been described for purposes ofillustration, it is to be understood that there may be variousmodifications within the general scope of the invention.

What is claimed is:

1. The method of making plow bottom parts of curved shape with boltholes and having a hard jacket and a soft core, which comprises,grinding and cutting out blanks from fiat rolled stock, chemically heattreating the separate blanks to condition them for the formation byquenching of a hard jacket, shaping the blanks while soft to finalshape, quenching the shaped 3G blanks from a heated condition,assembling the parts with others on a plow bottom, and light 4 grindingand polishing the composite plow surface.

2. The method of making plow bottom parts of curved shape with boltholes and having a hard jacket and a soft core, which comprises,hot-rolling and stack-annealing the stock in the fiat soft strip form,grinding and cutting out blanks in flat soft form, bolt holes beingformed in the blank cutting operation, chemically heattreating theblanks to give them a penetrating hardenable jacket, die-forging the hotblanks to final shape, quenching the shaped blanks, assembling the partswith others on a plow bottom, and giving the composite surface a lightfinish grinding and polishing operation.

3. The method of making a curved plow moldboard having a hard jacketwith a soft core and with hard-surfaced bolt holes, which comprises,cutting and grinding blanks in the flat, heat treating the blanks in apenetrating atmosphere to provide a hardenable jacket, die forging thestill hot blanks to final shape, quenching the blanks, and finallygiving the parts a light surface finishing operation.

WILLIAM E. RUSKA.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 356,530 French Jan. 25, 1887 1,603,199 Erickson Oct. 12, 1926

